# 求 1 - 100 的和
thesum = 0
for i in range(1, 101):
    thesum += i

print(thesum)

# 求 300 - 400 的和
thesum = 0
for i in range (300, 401):
    thesum += i

print(thesum)

# 求 1 - 1000的和
for i in range(1, 1001):
    thesum += i

print(thesum)
